/*
 * Copyright (c) 1995, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
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 *
 */
package java.awt;

import java.util.Vector;
import java.util.Locale;
import java.util.EventListener;
import java.awt.peer.ListPeer;
import java.awt.event.*;
import java.io.ObjectOutputStream;
import java.io.ObjectInputStream;
import java.io.IOException;
import javax.accessibility.*;


/**
 * The <code>List</code> component presents the user with a scrolling list of text items. The list
 * can be set up so that the user can choose either one item or multiple items. <p> For example, the
 * code&nbsp;.&nbsp;.&nbsp;.
 *
 * <hr><blockquote><pre>
 * List lst = new List(4, false);
 * lst.add("Mercury");
 * lst.add("Venus");
 * lst.add("Earth");
 * lst.add("JavaSoft");
 * lst.add("Mars");
 * lst.add("Jupiter");
 * lst.add("Saturn");
 * lst.add("Uranus");
 * lst.add("Neptune");
 * lst.add("Pluto");
 * cnt.add(lst);
 * </pre></blockquote><hr>
 * <p> where <code>cnt</code> is a container, produces the following scrolling list: <p> <img
 * src="doc-files/List-1.gif" alt="Shows a list containing: Venus, Earth, JavaSoft, and Mars.
 * Javasoft is selected." style="float:center; margin: 7px 10px;"> <p> If the List allows multiple
 * selections, then clicking on an item that is already selected deselects it. In the preceding
 * example, only one item from the scrolling list can be selected at a time, since the second
 * argument when creating the new scrolling list is <code>false</code>. If the List does not allow
 * multiple selections, selecting an item causes any other selected item to be deselected. <p> Note
 * that the list in the example shown was created with four visible rows.  Once the list has been
 * created, the number of visible rows cannot be changed.  A default <code>List</code> is created
 * with four rows, so that <code>lst = new List()</code> is equivalent to <code>list = new List(4,
 * false)</code>. <p> Beginning with Java&nbsp;1.1, the Abstract Window Toolkit sends the
 * <code>List</code> object all mouse, keyboard, and focus events that occur over it. (The old AWT
 * event model is being maintained only for backwards compatibility, and its use is discouraged.)
 * <p> When an item is selected or deselected by the user, AWT sends an instance of
 * <code>ItemEvent</code> to the list. When the user double-clicks on an item in a scrolling list,
 * AWT sends an instance of <code>ActionEvent</code> to the list following the item event. AWT also
 * generates an action event when the user presses the return key while an item in the list is
 * selected. <p> If an application wants to perform some action based on an item in this list being
 * selected or activated by the user, it should implement <code>ItemListener</code> or
 * <code>ActionListener</code> as appropriate and register the new listener to receive events from
 * this list. <p> For multiple-selection scrolling lists, it is considered a better user interface
 * to use an external gesture (such as clicking on a button) to trigger the action.
 *
 * @author Sami Shaio
 * @see java.awt.event.ItemEvent
 * @see java.awt.event.ItemListener
 * @see java.awt.event.ActionEvent
 * @see java.awt.event.ActionListener
 * @since JDK1.0
 */
public class List extends Component implements ItemSelectable, Accessible {

  /**
   * A vector created to contain items which will become
   * part of the List Component.
   *
   * @serial
   * @see #addItem(String)
   * @see #getItem(int)
   */
  Vector<String> items = new Vector<>();

  /**
   * This field will represent the number of visible rows in the
   * <code>List</code> Component.  It is specified only once, and
   * that is when the list component is actually
   * created.  It will never change.
   *
   * @serial
   * @see #getRows()
   */
  int rows = 0;

  /**
   * <code>multipleMode</code> is a variable that will
   * be set to <code>true</code> if a list component is to be set to
   * multiple selection mode, that is where the user can
   * select more than one item in a list at one time.
   * <code>multipleMode</code> will be set to false if the
   * list component is set to single selection, that is where
   * the user can only select one item on the list at any
   * one time.
   *
   * @serial
   * @see #isMultipleMode()
   * @see #setMultipleMode(boolean)
   */
  boolean multipleMode = false;

  /**
   * <code>selected</code> is an array that will contain
   * the indices of items that have been selected.
   *
   * @serial
   * @see #getSelectedIndexes()
   * @see #getSelectedIndex()
   */
  int selected[] = new int[0];

  /**
   * This variable contains the value that will be used
   * when trying to make a particular list item visible.
   *
   * @serial
   * @see #makeVisible(int)
   */
  int visibleIndex = -1;

  transient ActionListener actionListener;
  transient ItemListener itemListener;

  private static final String base = "list";
  private static int nameCounter = 0;

  /*
   * JDK 1.1 serialVersionUID
   */
  private static final long serialVersionUID = -3304312411574666869L;

  /**
   * Creates a new scrolling list.
   * By default, there are four visible lines and multiple selections are
   * not allowed.  Note that this is a convenience method for
   * <code>List(0, false)</code>.  Also note that the number of visible
   * lines in the list cannot be changed after it has been created.
   *
   * @throws HeadlessException if GraphicsEnvironment.isHeadless() returns true.
   * @see java.awt.GraphicsEnvironment#isHeadless
   */
  public List() throws HeadlessException {
    this(0, false);
  }

  /**
   * Creates a new scrolling list initialized with the specified
   * number of visible lines. By default, multiple selections are
   * not allowed.  Note that this is a convenience method for
   * <code>List(rows, false)</code>.  Also note that the number
   * of visible rows in the list cannot be changed after it has
   * been created.
   *
   * @param rows the number of items to show.
   * @throws HeadlessException if GraphicsEnvironment.isHeadless() returns true.
   * @see java.awt.GraphicsEnvironment#isHeadless
   * @since JDK1.1
   */
  public List(int rows) throws HeadlessException {
    this(rows, false);
  }

  /**
   * The default number of visible rows is 4.  A list with
   * zero rows is unusable and unsightly.
   */
  final static int DEFAULT_VISIBLE_ROWS = 4;

  /**
   * Creates a new scrolling list initialized to display the specified
   * number of rows. Note that if zero rows are specified, then
   * the list will be created with a default of four rows.
   * Also note that the number of visible rows in the list cannot
   * be changed after it has been created.
   * If the value of <code>multipleMode</code> is
   * <code>true</code>, then the user can select multiple items from
   * the list. If it is <code>false</code>, only one item at a time
   * can be selected.
   *
   * @param rows the number of items to show.
   * @param multipleMode if <code>true</code>, then multiple selections are allowed; otherwise, only
   * one item can be selected at a time.
   * @throws HeadlessException if GraphicsEnvironment.isHeadless() returns true.
   * @see java.awt.GraphicsEnvironment#isHeadless
   */
  public List(int rows, boolean multipleMode) throws HeadlessException {
    GraphicsEnvironment.checkHeadless();
    this.rows = (rows != 0) ? rows : DEFAULT_VISIBLE_ROWS;
    this.multipleMode = multipleMode;
  }

  /**
   * Construct a name for this component.  Called by
   * <code>getName</code> when the name is <code>null</code>.
   */
  String constructComponentName() {
    synchronized (List.class) {
      return base + nameCounter++;
    }
  }

  /**
   * Creates the peer for the list.  The peer allows us to modify the
   * list's appearance without changing its functionality.
   */
  public void addNotify() {
    synchronized (getTreeLock()) {
      if (peer == null) {
        peer = getToolkit().createList(this);
      }
      super.addNotify();
    }
  }

  /**
   * Removes the peer for this list.  The peer allows us to modify the
   * list's appearance without changing its functionality.
   */
  public void removeNotify() {
    synchronized (getTreeLock()) {
      ListPeer peer = (ListPeer) this.peer;
      if (peer != null) {
        selected = peer.getSelectedIndexes();
      }
      super.removeNotify();
    }
  }

  /**
   * Gets the number of items in the list.
   *
   * @return the number of items in the list
   * @see #getItem
   * @since JDK1.1
   */
  public int getItemCount() {
    return countItems();
  }

  /**
   * @deprecated As of JDK version 1.1, replaced by <code>getItemCount()</code>.
   */
  @Deprecated
  public int countItems() {
    return items.size();
  }

  /**
   * Gets the item associated with the specified index.
   *
   * @param index the position of the item
   * @return an item that is associated with the specified index
   * @see #getItemCount
   */
  public String getItem(int index) {
    return getItemImpl(index);
  }

  // NOTE: This method may be called by privileged threads.
  //       We implement this functionality in a package-private method
  //       to insure that it cannot be overridden by client subclasses.
  //       DO NOT INVOKE CLIENT CODE ON THIS THREAD!
  final String getItemImpl(int index) {
    return items.elementAt(index);
  }

  /**
   * Gets the items in the list.
   *
   * @return a string array containing items of the list
   * @see #select
   * @see #deselect
   * @see #isIndexSelected
   * @since JDK1.1
   */
  public synchronized String[] getItems() {
    String itemCopies[] = new String[items.size()];
    items.copyInto(itemCopies);
    return itemCopies;
  }

  /**
   * Adds the specified item to the end of scrolling list.
   *
   * @param item the item to be added
   * @since JDK1.1
   */
  public void add(String item) {
    addItem(item);
  }

  /**
   * @deprecated replaced by <code>add(String)</code>.
   */
  @Deprecated
  public void addItem(String item) {
    addItem(item, -1);
  }

  /**
   * Adds the specified item to the the scrolling list
   * at the position indicated by the index.  The index is
   * zero-based.  If the value of the index is less than zero,
   * or if the value of the index is greater than or equal to
   * the number of items in the list, then the item is added
   * to the end of the list.
   *
   * @param item the item to be added; if this parameter is <code>null</code> then the item is
   * treated as an empty string, <code>""</code>
   * @param index the position at which to add the item
   * @since JDK1.1
   */
  public void add(String item, int index) {
    addItem(item, index);
  }

  /**
   * @deprecated replaced by <code>add(String, int)</code>.
   */
  @Deprecated
  public synchronized void addItem(String item, int index) {
    if (index < -1 || index >= items.size()) {
      index = -1;
    }

    if (item == null) {
      item = "";
    }

    if (index == -1) {
      items.addElement(item);
    } else {
      items.insertElementAt(item, index);
    }

    ListPeer peer = (ListPeer) this.peer;
    if (peer != null) {
      peer.add(item, index);
    }
  }

  /**
   * Replaces the item at the specified index in the scrolling list
   * with the new string.
   *
   * @param newValue a new string to replace an existing item
   * @param index the position of the item to replace
   * @throws ArrayIndexOutOfBoundsException if <code>index</code> is out of range
   */
  public synchronized void replaceItem(String newValue, int index) {
    remove(index);
    add(newValue, index);
  }

  /**
   * Removes all items from this list.
   *
   * @see #remove
   * @see #delItems
   * @since JDK1.1
   */
  public void removeAll() {
    clear();
  }

  /**
   * @deprecated As of JDK version 1.1, replaced by <code>removeAll()</code>.
   */
  @Deprecated
  public synchronized void clear() {
    ListPeer peer = (ListPeer) this.peer;
    if (peer != null) {
      peer.removeAll();
    }
    items = new Vector<>();
    selected = new int[0];
  }

  /**
   * Removes the first occurrence of an item from the list.
   * If the specified item is selected, and is the only selected
   * item in the list, the list is set to have no selection.
   *
   * @param item the item to remove from the list
   * @throws IllegalArgumentException if the item doesn't exist in the list
   * @since JDK1.1
   */
  public synchronized void remove(String item) {
    int index = items.indexOf(item);
    if (index < 0) {
      throw new IllegalArgumentException("item " + item +
          " not found in list");
    } else {
      remove(index);
    }
  }

  /**
   * Removes the item at the specified position
   * from this scrolling list.
   * If the item with the specified position is selected, and is the
   * only selected item in the list, the list is set to have no selection.
   *
   * @param position the index of the item to delete
   * @throws ArrayIndexOutOfBoundsException if the <code>position</code> is less than 0 or greater
   * than <code>getItemCount()-1</code>
   * @see #add(String, int)
   * @since JDK1.1
   */
  public void remove(int position) {
    delItem(position);
  }

  /**
   * @deprecated replaced by <code>remove(String)</code> and <code>remove(int)</code>.
   */
  @Deprecated
  public void delItem(int position) {
    delItems(position, position);
  }

  /**
   * Gets the index of the selected item on the list,
   *
   * @return the index of the selected item; if no item is selected, or if multiple items are
   * selected, <code>-1</code> is returned.
   * @see #select
   * @see #deselect
   * @see #isIndexSelected
   */
  public synchronized int getSelectedIndex() {
    int sel[] = getSelectedIndexes();
    return (sel.length == 1) ? sel[0] : -1;
  }

  /**
   * Gets the selected indexes on the list.
   *
   * @return an array of the selected indexes on this scrolling list; if no item is selected, a
   * zero-length array is returned.
   * @see #select
   * @see #deselect
   * @see #isIndexSelected
   */
  public synchronized int[] getSelectedIndexes() {
    ListPeer peer = (ListPeer) this.peer;
    if (peer != null) {
      selected = peer.getSelectedIndexes();
    }
    return selected.clone();
  }

  /**
   * Gets the selected item on this scrolling list.
   *
   * @return the selected item on the list; if no item is selected, or if multiple items are
   * selected, <code>null</code> is returned.
   * @see #select
   * @see #deselect
   * @see #isIndexSelected
   */
  public synchronized String getSelectedItem() {
    int index = getSelectedIndex();
    return (index < 0) ? null : getItem(index);
  }

  /**
   * Gets the selected items on this scrolling list.
   *
   * @return an array of the selected items on this scrolling list; if no item is selected, a
   * zero-length array is returned.
   * @see #select
   * @see #deselect
   * @see #isIndexSelected
   */
  public synchronized String[] getSelectedItems() {
    int sel[] = getSelectedIndexes();
    String str[] = new String[sel.length];
    for (int i = 0; i < sel.length; i++) {
      str[i] = getItem(sel[i]);
    }
    return str;
  }

  /**
   * Gets the selected items on this scrolling list in an array of Objects.
   *
   * @return an array of <code>Object</code>s representing the selected items on this scrolling
   * list; if no item is selected, a zero-length array is returned.
   * @see #getSelectedItems
   * @see ItemSelectable
   */
  public Object[] getSelectedObjects() {
    return getSelectedItems();
  }

  /**
   * Selects the item at the specified index in the scrolling list.
   * <p>
   * Note that passing out of range parameters is invalid,
   * and will result in unspecified behavior.
   *
   * <p>Note that this method should be primarily used to
   * initially select an item in this component.
   * Programmatically calling this method will <i>not</i> trigger
   * an <code>ItemEvent</code>.  The only way to trigger an
   * <code>ItemEvent</code> is by user interaction.
   *
   * @param index the position of the item to select
   * @see #getSelectedItem
   * @see #deselect
   * @see #isIndexSelected
   */
  public void select(int index) {
    // Bug #4059614: select can't be synchronized while calling the peer,
    // because it is called from the Window Thread.  It is sufficient to
    // synchronize the code that manipulates 'selected' except for the
    // case where the peer changes.  To handle this case, we simply
    // repeat the selection process.

    ListPeer peer;
    do {
      peer = (ListPeer) this.peer;
      if (peer != null) {
        peer.select(index);
        return;
      }

      synchronized (this) {
        boolean alreadySelected = false;

        for (int i = 0; i < selected.length; i++) {
          if (selected[i] == index) {
            alreadySelected = true;
            break;
          }
        }

        if (!alreadySelected) {
          if (!multipleMode) {
            selected = new int[1];
            selected[0] = index;
          } else {
            int newsel[] = new int[selected.length + 1];
            System.arraycopy(selected, 0, newsel, 0,
                selected.length);
            newsel[selected.length] = index;
            selected = newsel;
          }
        }
      }
    } while (peer != this.peer);
  }

  /**
   * Deselects the item at the specified index.
   * <p>
   * Note that passing out of range parameters is invalid,
   * and will result in unspecified behavior.
   * <p>
   * If the item at the specified index is not selected,
   * then the operation is ignored.
   *
   * @param index the position of the item to deselect
   * @see #select
   * @see #getSelectedItem
   * @see #isIndexSelected
   */
  public synchronized void deselect(int index) {
    ListPeer peer = (ListPeer) this.peer;
    if (peer != null) {
      if (isMultipleMode() || (getSelectedIndex() == index)) {
        peer.deselect(index);
      }
    }

    for (int i = 0; i < selected.length; i++) {
      if (selected[i] == index) {
        int newsel[] = new int[selected.length - 1];
        System.arraycopy(selected, 0, newsel, 0, i);
        System.arraycopy(selected, i + 1, newsel, i, selected.length - (i + 1));
        selected = newsel;
        return;
      }
    }
  }

  /**
   * Determines if the specified item in this scrolling list is
   * selected.
   *
   * @param index the item to be checked
   * @return <code>true</code> if the specified item has been selected; <code>false</code> otherwise
   * @see #select
   * @see #deselect
   * @since JDK1.1
   */
  public boolean isIndexSelected(int index) {
    return isSelected(index);
  }

  /**
   * @deprecated As of JDK version 1.1, replaced by <code>isIndexSelected(int)</code>.
   */
  @Deprecated
  public boolean isSelected(int index) {
    int sel[] = getSelectedIndexes();
    for (int i = 0; i < sel.length; i++) {
      if (sel[i] == index) {
        return true;
      }
    }
    return false;
  }

  /**
   * Gets the number of visible lines in this list.  Note that
   * once the <code>List</code> has been created, this number
   * will never change.
   *
   * @return the number of visible lines in this scrolling list
   */
  public int getRows() {
    return rows;
  }

  /**
   * Determines whether this list allows multiple selections.
   *
   * @return <code>true</code> if this list allows multiple selections; otherwise,
   * <code>false</code>
   * @see #setMultipleMode
   * @since JDK1.1
   */
  public boolean isMultipleMode() {
    return allowsMultipleSelections();
  }

  /**
   * @deprecated As of JDK version 1.1, replaced by <code>isMultipleMode()</code>.
   */
  @Deprecated
  public boolean allowsMultipleSelections() {
    return multipleMode;
  }

  /**
   * Sets the flag that determines whether this list
   * allows multiple selections.
   * When the selection mode is changed from multiple-selection to
   * single-selection, the selected items change as follows:
   * If a selected item has the location cursor, only that
   * item will remain selected.  If no selected item has the
   * location cursor, all items will be deselected.
   *
   * @param b if <code>true</code> then multiple selections are allowed; otherwise, only one item
   * from the list can be selected at once
   * @see #isMultipleMode
   * @since JDK1.1
   */
  public void setMultipleMode(boolean b) {
    setMultipleSelections(b);
  }

  /**
   * @deprecated As of JDK version 1.1, replaced by <code>setMultipleMode(boolean)</code>.
   */
  @Deprecated
  public synchronized void setMultipleSelections(boolean b) {
    if (b != multipleMode) {
      multipleMode = b;
      ListPeer peer = (ListPeer) this.peer;
      if (peer != null) {
        peer.setMultipleMode(b);
      }
    }
  }

  /**
   * Gets the index of the item that was last made visible by
   * the method <code>makeVisible</code>.
   *
   * @return the index of the item that was last made visible
   * @see #makeVisible
   */
  public int getVisibleIndex() {
    return visibleIndex;
  }

  /**
   * Makes the item at the specified index visible.
   *
   * @param index the position of the item
   * @see #getVisibleIndex
   */
  public synchronized void makeVisible(int index) {
    visibleIndex = index;
    ListPeer peer = (ListPeer) this.peer;
    if (peer != null) {
      peer.makeVisible(index);
    }
  }

  /**
   * Gets the preferred dimensions for a list with the specified
   * number of rows.
   *
   * @param rows number of rows in the list
   * @return the preferred dimensions for displaying this scrolling list given that the specified
   * number of rows must be visible
   * @see java.awt.Component#getPreferredSize
   * @since JDK1.1
   */
  public Dimension getPreferredSize(int rows) {
    return preferredSize(rows);
  }

  /**
   * @deprecated As of JDK version 1.1, replaced by <code>getPreferredSize(int)</code>.
   */
  @Deprecated
  public Dimension preferredSize(int rows) {
    synchronized (getTreeLock()) {
      ListPeer peer = (ListPeer) this.peer;
      return (peer != null) ?
          peer.getPreferredSize(rows) :
          super.preferredSize();
    }
  }

  /**
   * Gets the preferred size of this scrolling list.
   *
   * @return the preferred dimensions for displaying this scrolling list
   * @see java.awt.Component#getPreferredSize
   * @since JDK1.1
   */
  public Dimension getPreferredSize() {
    return preferredSize();
  }

  /**
   * @deprecated As of JDK version 1.1, replaced by <code>getPreferredSize()</code>.
   */
  @Deprecated
  public Dimension preferredSize() {
    synchronized (getTreeLock()) {
      return (rows > 0) ?
          preferredSize(rows) :
          super.preferredSize();
    }
  }

  /**
   * Gets the minimum dimensions for a list with the specified
   * number of rows.
   *
   * @param rows number of rows in the list
   * @return the minimum dimensions for displaying this scrolling list given that the specified
   * number of rows must be visible
   * @see java.awt.Component#getMinimumSize
   * @since JDK1.1
   */
  public Dimension getMinimumSize(int rows) {
    return minimumSize(rows);
  }

  /**
   * @deprecated As of JDK version 1.1, replaced by <code>getMinimumSize(int)</code>.
   */
  @Deprecated
  public Dimension minimumSize(int rows) {
    synchronized (getTreeLock()) {
      ListPeer peer = (ListPeer) this.peer;
      return (peer != null) ?
          peer.getMinimumSize(rows) :
          super.minimumSize();
    }
  }

  /**
   * Determines the minimum size of this scrolling list.
   *
   * @return the minimum dimensions needed to display this scrolling list
   * @see java.awt.Component#getMinimumSize()
   * @since JDK1.1
   */
  public Dimension getMinimumSize() {
    return minimumSize();
  }

  /**
   * @deprecated As of JDK version 1.1, replaced by <code>getMinimumSize()</code>.
   */
  @Deprecated
  public Dimension minimumSize() {
    synchronized (getTreeLock()) {
      return (rows > 0) ? minimumSize(rows) : super.minimumSize();
    }
  }

  /**
   * Adds the specified item listener to receive item events from
   * this list.  Item events are sent in response to user input, but not
   * in response to calls to <code>select</code> or <code>deselect</code>.
   * If listener <code>l</code> is <code>null</code>,
   * no exception is thrown and no action is performed.
   * <p>Refer to <a href="doc-files/AWTThreadIssues.html#ListenersThreads"
   * >AWT Threading Issues</a> for details on AWT's threading model.
   *
   * @param l the item listener
   * @see #removeItemListener
   * @see #getItemListeners
   * @see #select
   * @see #deselect
   * @see java.awt.event.ItemEvent
   * @see java.awt.event.ItemListener
   * @since JDK1.1
   */
  public synchronized void addItemListener(ItemListener l) {
    if (l == null) {
      return;
    }
    itemListener = AWTEventMulticaster.add(itemListener, l);
    newEventsOnly = true;
  }

  /**
   * Removes the specified item listener so that it no longer
   * receives item events from this list.
   * If listener <code>l</code> is <code>null</code>,
   * no exception is thrown and no action is performed.
   * <p>Refer to <a href="doc-files/AWTThreadIssues.html#ListenersThreads"
   * >AWT Threading Issues</a> for details on AWT's threading model.
   *
   * @param l the item listener
   * @see #addItemListener
   * @see #getItemListeners
   * @see java.awt.event.ItemEvent
   * @see java.awt.event.ItemListener
   * @since JDK1.1
   */
  public synchronized void removeItemListener(ItemListener l) {
    if (l == null) {
      return;
    }
    itemListener = AWTEventMulticaster.remove(itemListener, l);
  }

  /**
   * Returns an array of all the item listeners
   * registered on this list.
   *
   * @return all of this list's <code>ItemListener</code>s or an empty array if no item listeners
   * are currently registered
   * @see #addItemListener
   * @see #removeItemListener
   * @see java.awt.event.ItemEvent
   * @see java.awt.event.ItemListener
   * @since 1.4
   */
  public synchronized ItemListener[] getItemListeners() {
    return getListeners(ItemListener.class);
  }

  /**
   * Adds the specified action listener to receive action events from
   * this list. Action events occur when a user double-clicks
   * on a list item or types Enter when the list has the keyboard
   * focus.
   * <p>
   * If listener <code>l</code> is <code>null</code>,
   * no exception is thrown and no action is performed.
   * <p>Refer to <a href="doc-files/AWTThreadIssues.html#ListenersThreads"
   * >AWT Threading Issues</a> for details on AWT's threading model.
   *
   * @param l the action listener
   * @see #removeActionListener
   * @see #getActionListeners
   * @see java.awt.event.ActionEvent
   * @see java.awt.event.ActionListener
   * @since JDK1.1
   */
  public synchronized void addActionListener(ActionListener l) {
    if (l == null) {
      return;
    }
    actionListener = AWTEventMulticaster.add(actionListener, l);
    newEventsOnly = true;
  }

  /**
   * Removes the specified action listener so that it no longer
   * receives action events from this list. Action events
   * occur when a user double-clicks on a list item.
   * If listener <code>l</code> is <code>null</code>,
   * no exception is thrown and no action is performed.
   * <p>Refer to <a href="doc-files/AWTThreadIssues.html#ListenersThreads"
   * >AWT Threading Issues</a> for details on AWT's threading model.
   *
   * @param l the action listener
   * @see #addActionListener
   * @see #getActionListeners
   * @see java.awt.event.ActionEvent
   * @see java.awt.event.ActionListener
   * @since JDK1.1
   */
  public synchronized void removeActionListener(ActionListener l) {
    if (l == null) {
      return;
    }
    actionListener = AWTEventMulticaster.remove(actionListener, l);
  }

  /**
   * Returns an array of all the action listeners
   * registered on this list.
   *
   * @return all of this list's <code>ActionListener</code>s or an empty array if no action
   * listeners are currently registered
   * @see #addActionListener
   * @see #removeActionListener
   * @see java.awt.event.ActionEvent
   * @see java.awt.event.ActionListener
   * @since 1.4
   */
  public synchronized ActionListener[] getActionListeners() {
    return getListeners(ActionListener.class);
  }

  /**
   * Returns an array of all the objects currently registered
   * as <code><em>Foo</em>Listener</code>s
   * upon this <code>List</code>.
   * <code><em>Foo</em>Listener</code>s are registered using the
   * <code>add<em>Foo</em>Listener</code> method.
   *
   * <p>
   * You can specify the <code>listenerType</code> argument
   * with a class literal, such as
   * <code><em>Foo</em>Listener.class</code>.
   * For example, you can query a
   * <code>List</code> <code>l</code>
   * for its item listeners with the following code:
   *
   * <pre>ItemListener[] ils = (ItemListener[])(l.getListeners(ItemListener.class));</pre>
   *
   * If no such listeners exist, this method returns an empty array.
   *
   * @param listenerType the type of listeners requested; this parameter should specify an interface
   * that descends from <code>java.util.EventListener</code>
   * @return an array of all objects registered as <code><em>Foo</em>Listener</code>s on this list,
   * or an empty array if no such listeners have been added
   * @throws ClassCastException if <code>listenerType</code> doesn't specify a class or interface
   * that implements <code>java.util.EventListener</code>
   * @see #getItemListeners
   * @since 1.3
   */
  public <T extends EventListener> T[] getListeners(Class<T> listenerType) {
    EventListener l = null;
    if (listenerType == ActionListener.class) {
      l = actionListener;
    } else if (listenerType == ItemListener.class) {
      l = itemListener;
    } else {
      return super.getListeners(listenerType);
    }
    return AWTEventMulticaster.getListeners(l, listenerType);
  }

  // REMIND: remove when filtering is done at lower level
  boolean eventEnabled(AWTEvent e) {
    switch (e.id) {
      case ActionEvent.ACTION_PERFORMED:
        if ((eventMask & AWTEvent.ACTION_EVENT_MASK) != 0 ||
            actionListener != null) {
          return true;
        }
        return false;
      case ItemEvent.ITEM_STATE_CHANGED:
        if ((eventMask & AWTEvent.ITEM_EVENT_MASK) != 0 ||
            itemListener != null) {
          return true;
        }
        return false;
      default:
        break;
    }
    return super.eventEnabled(e);
  }

  /**
   * Processes events on this scrolling list. If an event is
   * an instance of <code>ItemEvent</code>, it invokes the
   * <code>processItemEvent</code> method. Else, if the
   * event is an instance of <code>ActionEvent</code>,
   * it invokes <code>processActionEvent</code>.
   * If the event is not an item event or an action event,
   * it invokes <code>processEvent</code> on the superclass.
   * <p>Note that if the event parameter is <code>null</code>
   * the behavior is unspecified and may result in an
   * exception.
   *
   * @param e the event
   * @see java.awt.event.ActionEvent
   * @see java.awt.event.ItemEvent
   * @see #processActionEvent
   * @see #processItemEvent
   * @since JDK1.1
   */
  protected void processEvent(AWTEvent e) {
    if (e instanceof ItemEvent) {
      processItemEvent((ItemEvent) e);
      return;
    } else if (e instanceof ActionEvent) {
      processActionEvent((ActionEvent) e);
      return;
    }
    super.processEvent(e);
  }

  /**
   * Processes item events occurring on this list by
   * dispatching them to any registered
   * <code>ItemListener</code> objects.
   * <p>
   * This method is not called unless item events are
   * enabled for this component. Item events are enabled
   * when one of the following occurs:
   * <ul>
   * <li>An <code>ItemListener</code> object is registered
   * via <code>addItemListener</code>.
   * <li>Item events are enabled via <code>enableEvents</code>.
   * </ul>
   * <p>Note that if the event parameter is <code>null</code>
   * the behavior is unspecified and may result in an
   * exception.
   *
   * @param e the item event
   * @see java.awt.event.ItemEvent
   * @see java.awt.event.ItemListener
   * @see #addItemListener
   * @see java.awt.Component#enableEvents
   * @since JDK1.1
   */
  protected void processItemEvent(ItemEvent e) {
    ItemListener listener = itemListener;
    if (listener != null) {
      listener.itemStateChanged(e);
    }
  }

  /**
   * Processes action events occurring on this component
   * by dispatching them to any registered
   * <code>ActionListener</code> objects.
   * <p>
   * This method is not called unless action events are
   * enabled for this component. Action events are enabled
   * when one of the following occurs:
   * <ul>
   * <li>An <code>ActionListener</code> object is registered
   * via <code>addActionListener</code>.
   * <li>Action events are enabled via <code>enableEvents</code>.
   * </ul>
   * <p>Note that if the event parameter is <code>null</code>
   * the behavior is unspecified and may result in an
   * exception.
   *
   * @param e the action event
   * @see java.awt.event.ActionEvent
   * @see java.awt.event.ActionListener
   * @see #addActionListener
   * @see java.awt.Component#enableEvents
   * @since JDK1.1
   */
  protected void processActionEvent(ActionEvent e) {
    ActionListener listener = actionListener;
    if (listener != null) {
      listener.actionPerformed(e);
    }
  }

  /**
   * Returns the parameter string representing the state of this
   * scrolling list. This string is useful for debugging.
   *
   * @return the parameter string of this scrolling list
   */
  protected String paramString() {
    return super.paramString() + ",selected=" + getSelectedItem();
  }

  /**
   * @deprecated As of JDK version 1.1, Not for public use in the future. This method is expected to
   * be retained only as a package private method.
   */
  @Deprecated
  public synchronized void delItems(int start, int end) {
    for (int i = end; i >= start; i--) {
      items.removeElementAt(i);
    }
    ListPeer peer = (ListPeer) this.peer;
    if (peer != null) {
      peer.delItems(start, end);
    }
  }

    /*
     * Serialization support.  Since the value of the selected
     * field isn't necessarily up to date, we sync it up with the
     * peer before serializing.
     */

  /**
   * The <code>List</code> component's
   * Serialized Data Version.
   *
   * @serial
   */
  private int listSerializedDataVersion = 1;

  /**
   * Writes default serializable fields to stream.  Writes
   * a list of serializable <code>ItemListeners</code>
   * and <code>ActionListeners</code> as optional data.
   * The non-serializable listeners are detected and
   * no attempt is made to serialize them.
   *
   * @param s the <code>ObjectOutputStream</code> to write
   * @serialData <code>null</code> terminated sequence of 0 or more pairs; the pair consists of a
   * <code>String</code> and an <code>Object</code>; the <code>String</code> indicates the type of
   * object and is one of the following: <code>itemListenerK</code> indicating an
   * <code>ItemListener</code> object; <code>actionListenerK</code> indicating an
   * <code>ActionListener</code> object
   * @see AWTEventMulticaster#save(ObjectOutputStream, String, EventListener)
   * @see java.awt.Component#itemListenerK
   * @see java.awt.Component#actionListenerK
   * @see #readObject(ObjectInputStream)
   */
  private void writeObject(ObjectOutputStream s)
      throws IOException {
    synchronized (this) {
      ListPeer peer = (ListPeer) this.peer;
      if (peer != null) {
        selected = peer.getSelectedIndexes();
      }
    }
    s.defaultWriteObject();

    AWTEventMulticaster.save(s, itemListenerK, itemListener);
    AWTEventMulticaster.save(s, actionListenerK, actionListener);
    s.writeObject(null);
  }

  /**
   * Reads the <code>ObjectInputStream</code> and if it
   * isn't <code>null</code> adds a listener to receive
   * both item events and action events (as specified
   * by the key stored in the stream) fired by the
   * <code>List</code>.
   * Unrecognized keys or values will be ignored.
   *
   * @param s the <code>ObjectInputStream</code> to write
   * @throws HeadlessException if <code>GraphicsEnvironment.isHeadless</code> returns
   * <code>true</code>
   * @see #removeItemListener(ItemListener)
   * @see #addItemListener(ItemListener)
   * @see java.awt.GraphicsEnvironment#isHeadless
   * @see #writeObject(ObjectOutputStream)
   */
  private void readObject(ObjectInputStream s)
      throws ClassNotFoundException, IOException, HeadlessException {
    GraphicsEnvironment.checkHeadless();
    s.defaultReadObject();

    Object keyOrNull;
    while (null != (keyOrNull = s.readObject())) {
      String key = ((String) keyOrNull).intern();

      if (itemListenerK == key) {
        addItemListener((ItemListener) (s.readObject()));
      } else if (actionListenerK == key) {
        addActionListener((ActionListener) (s.readObject()));
      } else // skip value for unrecognized key
      {
        s.readObject();
      }
    }
  }

/////////////////
// Accessibility support
////////////////


  /**
   * Gets the <code>AccessibleContext</code> associated with this
   * <code>List</code>. For lists, the <code>AccessibleContext</code>
   * takes the form of an <code>AccessibleAWTList</code>.
   * A new <code>AccessibleAWTList</code> instance is created, if necessary.
   *
   * @return an <code>AccessibleAWTList</code> that serves as the <code>AccessibleContext</code> of
   * this <code>List</code>
   * @since 1.3
   */
  public AccessibleContext getAccessibleContext() {
    if (accessibleContext == null) {
      accessibleContext = new AccessibleAWTList();
    }
    return accessibleContext;
  }

  /**
   * This class implements accessibility support for the
   * <code>List</code> class.  It provides an implementation of the
   * Java Accessibility API appropriate to list user-interface elements.
   *
   * @since 1.3
   */
  protected class AccessibleAWTList extends AccessibleAWTComponent
      implements AccessibleSelection, ItemListener, ActionListener {

    /*
     * JDK 1.3 serialVersionUID
     */
    private static final long serialVersionUID = 7924617370136012829L;

    public AccessibleAWTList() {
      super();
      List.this.addActionListener(this);
      List.this.addItemListener(this);
    }

    public void actionPerformed(ActionEvent event) {
    }

    public void itemStateChanged(ItemEvent event) {
    }

    /**
     * Get the state set of this object.
     *
     * @return an instance of AccessibleState containing the current state of the object
     * @see AccessibleState
     */
    public AccessibleStateSet getAccessibleStateSet() {
      AccessibleStateSet states = super.getAccessibleStateSet();
      if (List.this.isMultipleMode()) {
        states.add(AccessibleState.MULTISELECTABLE);
      }
      return states;
    }

    /**
     * Get the role of this object.
     *
     * @return an instance of AccessibleRole describing the role of the object
     * @see AccessibleRole
     */
    public AccessibleRole getAccessibleRole() {
      return AccessibleRole.LIST;
    }

    /**
     * Returns the Accessible child contained at the local coordinate
     * Point, if one exists.
     *
     * @return the Accessible at the specified location, if it exists
     */
    public Accessible getAccessibleAt(Point p) {
      return null; // fredxFIXME Not implemented yet
    }

    /**
     * Returns the number of accessible children in the object.  If all
     * of the children of this object implement Accessible, than this
     * method should return the number of children of this object.
     *
     * @return the number of accessible children in the object.
     */
    public int getAccessibleChildrenCount() {
      return List.this.getItemCount();
    }

    /**
     * Return the nth Accessible child of the object.
     *
     * @param i zero-based index of child
     * @return the nth Accessible child of the object
     */
    public Accessible getAccessibleChild(int i) {
      synchronized (List.this) {
        if (i >= List.this.getItemCount()) {
          return null;
        } else {
          return new AccessibleAWTListChild(List.this, i);
        }
      }
    }

    /**
     * Get the AccessibleSelection associated with this object.  In the
     * implementation of the Java Accessibility API for this class,
     * return this object, which is responsible for implementing the
     * AccessibleSelection interface on behalf of itself.
     *
     * @return this object
     */
    public AccessibleSelection getAccessibleSelection() {
      return this;
    }

    // AccessibleSelection methods

    /**
     * Returns the number of items currently selected.
     * If no items are selected, the return value will be 0.
     *
     * @return the number of items currently selected.
     */
    public int getAccessibleSelectionCount() {
      return List.this.getSelectedIndexes().length;
    }

    /**
     * Returns an Accessible representing the specified selected item
     * in the object.  If there isn't a selection, or there are
     * fewer items selected than the integer passed in, the return
     * value will be null.
     *
     * @param i the zero-based index of selected items
     * @return an Accessible containing the selected item
     */
    public Accessible getAccessibleSelection(int i) {
      synchronized (List.this) {
        int len = getAccessibleSelectionCount();
        if (i < 0 || i >= len) {
          return null;
        } else {
          return getAccessibleChild(List.this.getSelectedIndexes()[i]);
        }
      }
    }

    /**
     * Returns true if the current child of this object is selected.
     *
     * @param i the zero-based index of the child in this Accessible object.
     * @see AccessibleContext#getAccessibleChild
     */
    public boolean isAccessibleChildSelected(int i) {
      return List.this.isIndexSelected(i);
    }

    /**
     * Adds the specified selected item in the object to the object's
     * selection.  If the object supports multiple selections,
     * the specified item is added to any existing selection, otherwise
     * it replaces any existing selection in the object.  If the
     * specified item is already selected, this method has no effect.
     *
     * @param i the zero-based index of selectable items
     */
    public void addAccessibleSelection(int i) {
      List.this.select(i);
    }

    /**
     * Removes the specified selected item in the object from the object's
     * selection.  If the specified item isn't currently selected, this
     * method has no effect.
     *
     * @param i the zero-based index of selectable items
     */
    public void removeAccessibleSelection(int i) {
      List.this.deselect(i);
    }

    /**
     * Clears the selection in the object, so that nothing in the
     * object is selected.
     */
    public void clearAccessibleSelection() {
      synchronized (List.this) {
        int selectedIndexes[] = List.this.getSelectedIndexes();
        if (selectedIndexes == null) {
          return;
        }
        for (int i = selectedIndexes.length - 1; i >= 0; i--) {
          List.this.deselect(selectedIndexes[i]);
        }
      }
    }

    /**
     * Causes every selected item in the object to be selected
     * if the object supports multiple selections.
     */
    public void selectAllAccessibleSelection() {
      synchronized (List.this) {
        for (int i = List.this.getItemCount() - 1; i >= 0; i--) {
          List.this.select(i);
        }
      }
    }

    /**
     * This class implements accessibility support for
     * List children.  It provides an implementation of the
     * Java Accessibility API appropriate to list children
     * user-interface elements.
     *
     * @since 1.3
     */
    protected class AccessibleAWTListChild extends AccessibleAWTComponent
        implements Accessible {

      /*
       * JDK 1.3 serialVersionUID
       */
      private static final long serialVersionUID = 4412022926028300317L;

      // [[[FIXME]]] need to finish implementing this!!!

      private List parent;
      private int indexInParent;

      public AccessibleAWTListChild(List parent, int indexInParent) {
        this.parent = parent;
        this.setAccessibleParent(parent);
        this.indexInParent = indexInParent;
      }

      //
      // required Accessible methods
      //

      /**
       * Gets the AccessibleContext for this object.  In the
       * implementation of the Java Accessibility API for this class,
       * return this object, which acts as its own AccessibleContext.
       *
       * @return this object
       */
      public AccessibleContext getAccessibleContext() {
        return this;
      }

      //
      // required AccessibleContext methods
      //

      /**
       * Get the role of this object.
       *
       * @return an instance of AccessibleRole describing the role of the object
       * @see AccessibleRole
       */
      public AccessibleRole getAccessibleRole() {
        return AccessibleRole.LIST_ITEM;
      }

      /**
       * Get the state set of this object.  The AccessibleStateSet of an
       * object is composed of a set of unique AccessibleState's.  A
       * change in the AccessibleStateSet of an object will cause a
       * PropertyChangeEvent to be fired for the
       * ACCESSIBLE_STATE_PROPERTY property.
       *
       * @return an instance of AccessibleStateSet containing the current state set of the object
       * @see AccessibleStateSet
       * @see AccessibleState
       * @see #addPropertyChangeListener
       */
      public AccessibleStateSet getAccessibleStateSet() {
        AccessibleStateSet states = super.getAccessibleStateSet();
        if (parent.isIndexSelected(indexInParent)) {
          states.add(AccessibleState.SELECTED);
        }
        return states;
      }

      /**
       * Gets the locale of the component. If the component does not
       * have a locale, then the locale of its parent is returned.
       *
       * @return This component's locale.  If this component does not have a locale, the locale of
       * its parent is returned.
       * @throws IllegalComponentStateException If the Component does not have its own locale and
       * has not yet been added to a containment hierarchy such that the locale can be determined
       * from the containing parent.
       */
      public Locale getLocale() {
        return parent.getLocale();
      }

      /**
       * Get the 0-based index of this object in its accessible parent.
       *
       * @return the 0-based index of this object in its parent; -1 if this object does not have an
       * accessible parent.
       * @see #getAccessibleParent
       * @see #getAccessibleChildrenCount
       * @see #getAccessibleChild
       */
      public int getAccessibleIndexInParent() {
        return indexInParent;
      }

      /**
       * Returns the number of accessible children of the object.
       *
       * @return the number of accessible children of the object.
       */
      public int getAccessibleChildrenCount() {
        return 0;       // list elements can't have children
      }

      /**
       * Return the specified Accessible child of the object.  The
       * Accessible children of an Accessible object are zero-based,
       * so the first child of an Accessible child is at index 0, the
       * second child is at index 1, and so on.
       *
       * @param i zero-based index of child
       * @return the Accessible child of the object
       * @see #getAccessibleChildrenCount
       */
      public Accessible getAccessibleChild(int i) {
        return null;    // list elements can't have children
      }

      //
      // AccessibleComponent delegatation to parent List
      //

      /**
       * Get the background color of this object.
       *
       * @return the background color, if supported, of the object; otherwise, null
       * @see #setBackground
       */
      public Color getBackground() {
        return parent.getBackground();
      }

      /**
       * Set the background color of this object.
       *
       * @param c the new Color for the background
       * @see #setBackground
       */
      public void setBackground(Color c) {
        parent.setBackground(c);
      }

      /**
       * Get the foreground color of this object.
       *
       * @return the foreground color, if supported, of the object; otherwise, null
       * @see #setForeground
       */
      public Color getForeground() {
        return parent.getForeground();
      }

      /**
       * Set the foreground color of this object.
       *
       * @param c the new Color for the foreground
       * @see #getForeground
       */
      public void setForeground(Color c) {
        parent.setForeground(c);
      }

      /**
       * Get the Cursor of this object.
       *
       * @return the Cursor, if supported, of the object; otherwise, null
       * @see #setCursor
       */
      public Cursor getCursor() {
        return parent.getCursor();
      }

      /**
       * Set the Cursor of this object.
       * <p>
       * The method may have no visual effect if the Java platform
       * implementation and/or the native system do not support
       * changing the mouse cursor shape.
       *
       * @param cursor the new Cursor for the object
       * @see #getCursor
       */
      public void setCursor(Cursor cursor) {
        parent.setCursor(cursor);
      }

      /**
       * Get the Font of this object.
       *
       * @return the Font,if supported, for the object; otherwise, null
       * @see #setFont
       */
      public Font getFont() {
        return parent.getFont();
      }

      /**
       * Set the Font of this object.
       *
       * @param f the new Font for the object
       * @see #getFont
       */
      public void setFont(Font f) {
        parent.setFont(f);
      }

      /**
       * Get the FontMetrics of this object.
       *
       * @param f the Font
       * @return the FontMetrics, if supported, the object; otherwise, null
       * @see #getFont
       */
      public FontMetrics getFontMetrics(Font f) {
        return parent.getFontMetrics(f);
      }

      /**
       * Determine if the object is enabled.  Objects that are enabled
       * will also have the AccessibleState.ENABLED state set in their
       * AccessibleStateSet.
       *
       * @return true if object is enabled; otherwise, false
       * @see #setEnabled
       * @see AccessibleContext#getAccessibleStateSet
       * @see AccessibleState#ENABLED
       * @see AccessibleStateSet
       */
      public boolean isEnabled() {
        return parent.isEnabled();
      }

      /**
       * Set the enabled state of the object.
       *
       * @param b if true, enables this object; otherwise, disables it
       * @see #isEnabled
       */
      public void setEnabled(boolean b) {
        parent.setEnabled(b);
      }

      /**
       * Determine if the object is visible.  Note: this means that the
       * object intends to be visible; however, it may not be
       * showing on the screen because one of the objects that this object
       * is contained by is currently not visible.  To determine if an
       * object is showing on the screen, use isShowing().
       * <p>Objects that are visible will also have the
       * AccessibleState.VISIBLE state set in their AccessibleStateSet.
       *
       * @return true if object is visible; otherwise, false
       * @see #setVisible
       * @see AccessibleContext#getAccessibleStateSet
       * @see AccessibleState#VISIBLE
       * @see AccessibleStateSet
       */
      public boolean isVisible() {
        // [[[FIXME]]] needs to work like isShowing() below
        return false;
        // return parent.isVisible();
      }

      /**
       * Set the visible state of the object.
       *
       * @param b if true, shows this object; otherwise, hides it
       * @see #isVisible
       */
      public void setVisible(boolean b) {
        // [[[FIXME]]] should scroll to item to make it show!
        parent.setVisible(b);
      }

      /**
       * Determine if the object is showing.  This is determined by
       * checking the visibility of the object and visibility of the
       * object ancestors.
       * Note: this will return true even if the object is obscured
       * by another (for example, it to object is underneath a menu
       * that was pulled down).
       *
       * @return true if object is showing; otherwise, false
       */
      public boolean isShowing() {
        // [[[FIXME]]] only if it's showing!!!
        return false;
        // return parent.isShowing();
      }

      /**
       * Checks whether the specified point is within this object's
       * bounds, where the point's x and y coordinates are defined to
       * be relative to the coordinate system of the object.
       *
       * @param p the Point relative to the coordinate system of the object
       * @return true if object contains Point; otherwise false
       * @see #getBounds
       */
      public boolean contains(Point p) {
        // [[[FIXME]]] - only if p is within the list element!!!
        return false;
        // return parent.contains(p);
      }

      /**
       * Returns the location of the object on the screen.
       *
       * @return location of object on screen; null if this object is not on the screen
       * @see #getBounds
       * @see #getLocation
       */
      public Point getLocationOnScreen() {
        // [[[FIXME]]] sigh
        return null;
      }

      /**
       * Gets the location of the object relative to the parent in the
       * form of a point specifying the object's top-left corner in the
       * screen's coordinate space.
       *
       * @return An instance of Point representing the top-left corner of the objects's bounds in
       * the coordinate space of the screen; null if this object or its parent are not on the
       * screen
       * @see #getBounds
       * @see #getLocationOnScreen
       */
      public Point getLocation() {
        // [[[FIXME]]]
        return null;
      }

      /**
       * Sets the location of the object relative to the parent.
       *
       * @param p the new position for the top-left corner
       * @see #getLocation
       */
      public void setLocation(Point p) {
        // [[[FIXME]]] maybe - can simply return as no-op
      }

      /**
       * Gets the bounds of this object in the form of a Rectangle object.
       * The bounds specify this object's width, height, and location
       * relative to its parent.
       *
       * @return A rectangle indicating this component's bounds; null if this object is not on the
       * screen.
       * @see #contains
       */
      public Rectangle getBounds() {
        // [[[FIXME]]]
        return null;
      }

      /**
       * Sets the bounds of this object in the form of a Rectangle
       * object.  The bounds specify this object's width, height, and
       * location relative to its parent.
       *
       * @param r rectangle indicating this component's bounds
       * @see #getBounds
       */
      public void setBounds(Rectangle r) {
        // no-op; not supported
      }

      /**
       * Returns the size of this object in the form of a Dimension
       * object.  The height field of the Dimension object contains this
       * objects's height, and the width field of the Dimension object
       * contains this object's width.
       *
       * @return A Dimension object that indicates the size of this component; null if this object
       * is not on the screen
       * @see #setSize
       */
      public Dimension getSize() {
        // [[[FIXME]]]
        return null;
      }

      /**
       * Resizes this object so that it has width and height.
       *
       * @param d - The dimension specifying the new size of the object.
       * @see #getSize
       */
      public void setSize(Dimension d) {
        // not supported; no-op
      }

      /**
       * Returns the <code>Accessible</code> child, if one exists,
       * contained at the local coordinate <code>Point</code>.
       *
       * @param p the point relative to the coordinate system of this object
       * @return the <code>Accessible</code>, if it exists, at the specified location; otherwise
       * <code>null</code>
       */
      public Accessible getAccessibleAt(Point p) {
        return null;    // object cannot have children!
      }

      /**
       * Returns whether this object can accept focus or not.   Objects
       * that can accept focus will also have the
       * <code>AccessibleState.FOCUSABLE</code> state set in their
       * <code>AccessibleStateSet</code>.
       *
       * @return true if object can accept focus; otherwise false
       * @see AccessibleContext#getAccessibleStateSet
       * @see AccessibleState#FOCUSABLE
       * @see AccessibleState#FOCUSED
       * @see AccessibleStateSet
       */
      public boolean isFocusTraversable() {
        return false;   // list element cannot receive focus!
      }

      /**
       * Requests focus for this object.  If this object cannot accept
       * focus, nothing will happen.  Otherwise, the object will attempt
       * to take focus.
       *
       * @see #isFocusTraversable
       */
      public void requestFocus() {
        // nothing to do; a no-op
      }

      /**
       * Adds the specified focus listener to receive focus events from
       * this component.
       *
       * @param l the focus listener
       * @see #removeFocusListener
       */
      public void addFocusListener(FocusListener l) {
        // nothing to do; a no-op
      }

      /**
       * Removes the specified focus listener so it no longer receives
       * focus events from this component.
       *
       * @param l the focus listener
       * @see #addFocusListener
       */
      public void removeFocusListener(FocusListener l) {
        // nothing to do; a no-op
      }


    } // inner class AccessibleAWTListChild

  } // inner class AccessibleAWTList

}
